Fuel-propelled vehicles, such as rockets and missiles, utilize rocket motors to propel the vehicle through air and space. The rocket motors generally fall into three types, which are solid propellant motors, liquid propellant motors and hybrid propellant motors. Solid propellant motors utilize a solid fuel element or grain that is placed in a large solid combustion chamber. The solid fuel element or grain is usually bonded to the combustion chamber walls and burns away during flight. The liquid propellant motors employ liquid fuel tanks coupled to a fixed combustion chamber through one or more fuel lines. A hybrid propellant motor generally uses a fluid reactant (e.g., an oxidizer) to burn a solid fuel element or a fluid fuel element with a solid reactant, which are ignited in a combustion chamber. When the propellant is combusted, the resultant combustion reaction is typically propelled from one end of the fuel-propelled vehicle, and can be referred to as the vehicle exhaust plume. Typically, ultraviolet light is radiated from the vehicle exhaust plume.
Ultraviolet light detectors are utilized in rocket and missile defense systems. These ultraviolet light detectors can be mounted, for example, on an aircraft, or other vehicle that could be a target for one or more rockets and/or missiles. The rocket and missile defense systems employ optics and/or infrared technology to track rockets and/or missiles fired at or near the rocket and missile defense systems. The ultraviolet light detector can track rockets and/or missiles by detecting ultraviolet light provided by the plume of a rocket and/or missile. Typically, each type of rocket and/or missile has a different vehicle exhaust plume pattern, which can be referred to as the plume pattern. For instance, some missiles have longer effective ranges than others, thus requiring different rates of propellant combustion. Therefore, the intensity of the ultraviolet light provided by different types of missiles will be different. Additionally, the combustion of different forms of fuel (e.g., solid propellant, liquid propellant or hybrid propellant), can also provide different ultraviolet radiation patterns.
In one example, the detected intensity of the ultraviolet light provided by the rocket and/or missile can increase as the rocket and/or missile approaches the ultraviolet light detector. Additionally, when the rocket and/or missile is initially activated (e.g., fired), the ultraviolet light detector will typically detect a short pulse of increased intensity of ultraviolet light.
Obviously, it is not economically practical to test the detectors by firing live rockets and missiles. Therefore, plume simulators that provide ultraviolet light with a radiation pattern similar to the ultraviolet radiation pattern provided by the exhaust plume of rockets or missiles have been developed. The plume simulators typically employ at least one high power incandescent lamp to radiate the ultraviolet light needed to simulate an exhaust plume. Additionally, to simulate an initial burst of ultraviolet light, some plume simulators require the use of electromechanical shutters. However, incandescent lamps suffer from poor efficiency, a high failure rate and a relatively poor modulation rate, which make simulating a vehicle exhaust plume using incandescent lamps undesirable.